Cam activated hydraulic braking system

Abstract

A braking system controlled by an operator's pedal for a vehicle equipped with a mechanically actuated brake clutch pack in which a cam is rotated in response to movement of a brake pedal to operate a pressure-modulating hydraulic valve to direct fluid pressure to an hydraulic actuator extendable under pressure to engage a force transfer member secured to an actuator rod, which rod is connected to apply the clutch pack when tensioned.

What is claimed is: 
     
       1. A braking system controlled by an operator's pedal for a vehicle having a mechanically actuated brake clutch pack arranged for braking the vehicle comprising: a pressure-modulating hydraulic valve;   hydraulic pump for supplying hydraulic fluid under pressure to said valve;   a cam for operating said valve;   a rotatable shaft secured to said cam for rotation therewith;   a first arm attached to said shaft;   a first clevis pinned to said first arm;   an operating rod attached to said clevis and connected to said pedal for rotating said shaft in response to movement of said pedal;   a hydraulic actuator being extendable under pressure and connected to receive pressure from said valve;   an actuating rod connected, when tensioned, to apply said clutch pack; and   a force transfer member attached to said rod and engageable by said actuator for tensioning said rod as said actuator is extended, whereby the braking effort is related to the position of said pedal.   
     
     
       2. The invention according to claim 1, wherein said hydraulic actuator comprises: a cylinder having a tubular extension; and   a piston with an outer end having a hole extending therethrough reciprocal in said cylinder;   said actuating rod extending through said tubular extension and said hole.   
     
     
       3. The invention according to claim 2, and further comprising: a second arm attached to the shaft for rotation therewith; and   a second clevis pinned to said second arm and attached to said actuating rod;   whereby said actuating rod is tensioned, in the absence of hydraulic pressure, by rotation of said shaft.   
     
     
       4. The invention according to claim 3, and further comprising: a joint interposed in said actuating rod between the cylinder and said second clevis.   
     
     
       5. A braking system for a vehicle having a pair of tracks, each of which is driven by a final drive with a brake clutch pack mechanically actuated by an actuating lever to brake the vehicle, said vehicle having a driver operated pedal for application thereof, said system comprising: a base plate attached to said vehicle;   a shaft journaled on and supported by said base plate;   a cam affixed to said shaft;   a valve supported from said base plate and having a displaceable spool;   a cam follower carried by said spool and engaging said cam;   a first arm affixed to shaft and connected to said pedal for rotation of said shaft in response to movement of said pedal;   a hydraulic actuator being extendable and connected to receive hydraulic fluid under pressure from said valve;   a force transmitting member engageable with said actuator;   an actuating rod attached to said member and connected to said actuating levers to apply said brakes in response to depression of said pedal.   
     
     
       6. The invention according to claim 5, wherein said valve is a pressure-modulating valve. 
     
     
       7. The invention according to claim 6, wherein said actuator comprises: a cylinder connected to receive hydraulic fluid from said valve and having a tubular extension; and   a piston having an outer end with a hole therethrough reciprocal within said cylinder and extendable under hydraulic pressure;   said member being engageable with said outer end and said actuating rod extending through said hole and said tubular extension.   
     
     
       8. The invention according to claim 7, and further comprising: a second arm affixed to said shaft; and   a second clevis pinned to said second arm and connected to said actuating rod;   whereby rotation of said shaft will, in the absence of hydraulic pressure, permit said second arm to tension said arm as said shaft is rotated by said pedal to apply the brakes.   
     
     
       9. The invention according to claim 8, and further comprising a joint interposed in said actuating rod between said second clevis and said piston to permit said actuating rod to move freely within said hole and said tubular extension.